On the effect that acoustic boundary conditions have on the structural transitions in nematics in the field of ultrasonic compressional waves

Abstract

The peculiarities of the structural transition in a homeotropic layer of nematic liquid crystal (NLC) affected by compressional waves in a cell with acoustically soft or hard boundary conditions at its ends have been studied for the frequency range where the wavelength of viscous wave is smaller than the layer thickness, while the wavelength of the elastic wave in NLC exceeds the layer thickness. The data obtained are analyzed within the known theoretical models developed for these two geometries based on the unified hypothesis, which postulates the flow mechanism of the orientational effect of ultrasound on NLC.